I have them on and didn't get a fair test and tune night out of them but what we did run they were hooked up and rolling on a fairly slick surface. You have to follow Mike's Idea's on mechanical grip vs chemical grip. bigger tire more contact patch plus more narrow rim to put bite back into the tire rather than stretch it tight and take bite out and then pour chemicals at the rubber to put bite back in.
It's all about committing to a tire system and staying with it to find what makes it work the best.
Thanks Tim, I've talked to several people that have them, but haven't run them, or people that want to try them, but no one that has put effort into them (maybe they're not talking?). It's an appealing option to me, I've been running the 11.5 treads at Dixon speedway, and love them through the center of the corner, power delivery is hurting me center off, but that's another story.
I like the fact that they give about 1/2" more ground clearance, especially being a bigger guy and running a #430 kart, if the track is the slightest bit rough and Im on a 34" tire I spend more time with the frame rails on the ground than the tires...